10 g of a radioactive substance was placed in an airtight container 50 years ago. When the container is opened, only 2.5 g remains. What is the half-life of this material?
10 g of a radioactive substance was placed in an airtight container 50 years ago. When...
If a container of radioactive isotope has a half-life of 10 years, how many years will it take for there to only be 25% of the isotope remaining in the container.
a) You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 76.2 minutes , what is the half-life of this substance? b)An unknown radioactive substance has a half-life of 3.20 hours . If 14.6 g of the substance is currently present, what mass A0 was present 8.00 hours ago? c) Americium-241 is used in some smoke detectors. It...
A 50.0 mg sample of an unknown radioactive substance was placed
in storage and its mass measured periodically. After 70.9 days70.9
days, the amount of radioactive substance had decreased to 3.13
mg.
What is the half-life of the unknown radioactive substance?
half-life:
days
B) An unknown radioactive substance has a half-life of 3.20 hours. If 47.3 g of the substance is currently present, what mass A0 was present 8.00 hours ago? Express your answer with the appropriate units. C) Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 30.0 % of an Am-241 sample to decay? Express your answer with the appropriate units. D) A fossil...
A toxic radioactive substance with a density of 7 milligrams per square centimeter is detected in the ventilating ducts of a nuclear processing building that was used 45 years ago. If the half- life of the substance is 20 years, what was the density of the substance when it was deposited 45 years ago?
A) You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 48.2 minutes , what is the half-life of this substance? B) An unknown radioactive substance has a half-life of 3.20 hours . If 24.3 g of the substance is currently present, what mass A0 was present 8.00 hours ago? C) Americium-241 is used in some smoke detectors....
An unknown radioactive substance has a half-life of 3.20 hours. If 39.6 g of the substance is currently present, what mass Ao was present 8.00 hours ago? Express your answer with the appropriate units. View Available Hint(s) ? OP HÅR A9 = Value O 2 Units Submit Part C Americium-241 is used in some smoke detectors. It is an alpha emitter with a half-life of 432 years. How long will it take in years for 34.0 % of an Am-241...
A) You are using a Geiger counter to measure the activity of a radioactive substance over the course of several minutes. If the reading of 400. counts has diminished to 100. counts after 72.2 minutes , what is the half-life of this substance? Express your answer numerically in minutes. B) An unknown radioactive substance has a half-life of 3.20 hours . If 19.1 g of the substance is currently present, what mass A0 was present 8.00 hours ago? Express your...
If a 10 gram sample of a radioactive substance has a half-life of 6000 years, how much would be present after 8000 years?
The number of grams A of a certain radioactive substance present at time, in years from the present, t is given by the formula A=45e^-0.0045t What is initial amount of this substance What is half-life of this substance How much will be around in 2500 years